building gstreamer-plugins from SRPM

I'd like to build my own custom gstreamer-mp3 plugin so I started by
getting the SRPM for the gstreamer-plugin RPM and am trying to derrive
the MP3 RPM from it and the original gstreamer-plugin tar file from the
official gstreamer site.

I've tried to re-build the SRPM out-of-the box before making
modifications and I get these errors:

RPM build errors:
    File not found by glob:
/var/tmp/gstreamer-plugins-0.6.3-root/usr/lib/gstreamer-0.6/libgst1394.*^M
    File not found by glob:
/var/tmp/gstreamer-plugins-0.6.3-root/usr/lib/gstreamer-0.6/libgsthttpsrc.*^M
    File not found by glob:
/var/tmp/gstreamer-plugins-0.6.3-root/usr/lib/gstreamer-0.6/libgstpng.*^M
    File not found by glob:
/var/tmp/gstreamer-plugins-0.6.3-root/usr/lib/gstreamer-0.6/libgstsnapshot.*^M


Any idea why these files are not getting built?

Once I've tackled this problem, I'll be hacking the .spec file to build
a mp3 compatible RPM so I can get rhythmbox to work right.

Thanks.